what should the timing be with vac. hooked up at idle? At say 3000 rpm? Mine went from 11 degrees with vac plugged to 22 with it plugged isn't that a little much? Barry
Vacuum advance increases idle advance by 10-15 degrees...so you're good, if I'm reading that correctly.
Barry, I Don't Fool With The Vacumn Advance At All, It's Not Consistant. I Just Plug The Vacumn Ports And Concentrate On The Mechanical Advance, Which Can Easily Be Adjusted. Find A Curve Kit With The Limiting Bushing And Install It. Then Tune Your Distributor With The Weights And Springs That Give The Best Advance For Your Car. I Like 14-16 Degrees Initial With 36 Total At 2800 Rpm. Good Luck
Not having your arms around how the vacuum advance affects overall timing can be problematic, especially running higher compression ratios on pump gas. I run total mechanical advance set for best performance, then adjust to run as much vac advance (manifold vacuum) as possible without getting into part-throttle detonation. Takes some patience but it's well worth it. Here's a good thread started by Larry that can help you out: http://www.v8buick.com/showthread.php?t=63475 Devon
